// Given a string, compute recursively (no loops) the number of times
// lowercase “hi” appears in the string.
//
// countHi(“xxhixx”) → 1
// countHi(“xhixhix”) → 2
// countHi(“hi”) → 1
 
#include <stdio.h>
 
// To enable debug messages uncomment #define
#define TEST 1
 
int countHi(char *s);
void startTesting();
 
int main(void) {
#ifdef TEST
    startTesting();
#endif
 
	return 0;
}
 
int countHi(char *s) {
    if (*s == '\0' || *(s+1) == '\0') {
    	return 0;
    } else if (*s == 'h' && *(s+1) == 'i') {
    	return (1 + countHi(s + 2));
    } else {
    	return (countHi(++s));
    } 
}
 
void test1()
{
    int count = countHi("xxhixx");
    printf("countHi(\"xxhixx\") = %d\n", count);
}
 
void test2()
{
    int count = countHi("xhixhix");
    printf("countHi(\"xhixhix\") = %d\n", count);
}
 
void test3()
{
    int count = countHi("hi");
    printf("countHi(\"hi\") = %d\n", count);
} 
 
void startTesting()
{
    test1();
    test2();
    test3();
}